Never mind the confusion that you have two places to download from, the compiled CSS was breaking in FF and IE. Grid elements (small-6 columns) were not floating correctly. This was happening in spite of the fact that the CSS files available on the website are working fine.

So I am not so sure if the source on github can be trusted. And honestly Zurb should make the SCSS library available for download the same way they put out the CSS library on their site.

The CLI is totally optional. It scaffolds projects so you are ready out of the box and easily handles updates. The files in the CLI are the files in the bower-foundation repo. That is why they are kept there, so the package manager can use them to make a package. You can download the files and use Compass.